|1. Scales evident on abaxial surface of costae, with or without hairs.....2. ||2. Costal scale margins usually entire, sometimes denticulate but with no more than
one or two small hairs.....3.
||3. Costal scales linear and inconspicuous, no wider than 0.4mm .....Cheilanthes tomentosa.
||3. Costal scales lanceolate and more than 0.4mm wide.....4.
||4. Both adaxial and abaxial surfaces are devoid of cilia (if cilia are visible on abaxial surface, consider C. wootonii), plants are usually found on north facing exposure.....Cheilanthes fendleri.
||4. Cilia present on both adaxial and abaxial surfaces of terminal segments, plants commonly on south or east facing exposure (but if scales cover the abaxial surface of the terminal segments, look for cilia on the proximal part of the scales and consider C. lindheimeri) .....Cheilanthes eatonii.
||2. Costal scale margins with cilia over at least 1/2 their length .....5.
||5. Adaxial surface densely tomentose, ciliate scales obscure the abaxial terminal segments (otherwise, consider C. eatonii).....Cheilanthes lindheimeri.
||5. Adaxial surface glabrous or sparsely pubescent.....6.
||6. Pinnae glabrous adaxially, stem scales not bicolored; distal portion of costal scales
frequently without cilia.....Cheilanthes wootonii.
||6. Pinnae with sparse adaxial pubescence, costal scales usually ciliate for their entire length, stem scales bicolored and persistant.....Cheilanthes yavapensis.
|1. Scales absent from abaxial surface of costae, with or without hairs.....7.||
||7. Most fronds over 20cm tall, obviously pinnate-pinnatifid pinnae articulate to
rachis through a swollen node.....Cheilanthes bonariensis.
||7. Most fronds less than 20cm tall and commonly more than twice pinnate toward the base, pinnae do not articulate to rachis through a swollen node.....8.
||8. Most plants growing tightly clustered on nearly vertical cliff faces, rachis not grooved, abaxial surface of terminal segments densely hairly.....Cheilanthes feei.
||8. Most plants spreading in cracks in bedrock on sloping but not vertical terrain, rachis grooved, abaxial surface of terminal segments nearly glabrous.....Cheilanthes wrightii.